It looks as if the Heskey and Owen partnership has reached the iconic stage. The statistic of 14 goals in 14 starts or 12 starts together (and that was before Russia and Israel)  crops up in almost every article about them. It seemed to me that given that both of these players started their careers in the late nineties and that Owen has 85 caps and Heskey 45 that 12 or 14 starts together seemed very low.
I might be missing something (and it certainly becomes difficult to track appearances because of substitutions) but this is what I have come up with in terms of starting together and goals.

Russia Sept 12/07                   Owen 2,  Heskey 0.
Israel Sept 8/07                        Owen 1,  Heskey 0.
Croatia Aug 20/03                    Owen 1,  Heskey 0.
Serbia & Mont. June 3/03       Owen 0,  Heskey 0.
South Africa May 22/03            Owen 0,  Heskey 1.
Liechtenstein Mach 29/03      Owen 1,  Heskey  0.
Slovakia Oct 12/02                   Owen 1,  Heskey  0.
Portugal Sept 7/02                   Owen 0,  Heskey  0.
Brazil June 21/02                     Owen 1,  Heskey  0.
Denmark June 15/02              Owen 1,  Heskey  1.
Nigeria June 12/07                  Owen 0,  Heskey  0.
Argentina June 7/02                Owen 0,   Heskey  0.
Sweden June 2/02                   Owen 0,  Heskey 0.
Cameroon May 26/02              Owen 0,  Heskey 0.
South Korea May 21/02           Owen 1,  Heskey 0.
Italy March 27/02                       Owen 0,  Heskey 0.
Albania Sept 5/01                     Owen 1,  Heskey 0.
Germany Sept 1/01                  Owen 3,  Heskey 1.
Greece June 6/01                     Owen 0,  Heskey 0.
Mexico May 25/01                      Owen 0,  Heskey 0. 

I make that 20 starts together with Owen scoring 13 and Heskey 3. Still a decent strike rate but not what has been widely reported.
In all it appears to me that they have played in 32 games together although they may not have been on the park at the same time when one has replaced the other.
I used the FA archives as a source and I would be more than happy to admit an error if someone can come up with support for the 14 goals in 14 or 12 starts statistic. I did rattle this off quickly.